Process for producing aluminum-based metal composite, aluminum-based composite obtained by using the same, and aluminum-based structure having the aluminum-based composite

ABSTRACT

A process for producing aluminum-based metal composite, an aluminum-based composite obtained by using the same, and an aluminum-based structure having the said aluminum-based composite are provided. The aluminum-based metal treating method applies borax on the surface of an aluminum-based metal and heats such metal to a temperature over the melting point of borax. The aluminum-based composite includes aluminum in the range of 7 to 9 atomic %, sodium in the range of 11 to 13 atomic %, and oxygen in the range of 79 to 81 atomic %. The aluminum-based structure includes an aluminum-based substrate formed by an aluminum-based metal and an aluminum-based composite disposed in the aluminum based substrate.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention generally relates to a process for producing aluminum-based metal composite, an aluminum-based composite obtained by using the same, and an aluminum-based structure having the said aluminum-based composite.

2. Description of the Prior Art

Metal matrix composite (MMC) is a novel composite obtained by using special process to distribute different kinds and types of ceramic and non-metallic strengthened phase uniformly in a continuous metallic substrate. It has the advantages of metallic substrate and strengthened phase, e.g. high specific strength and specific stiffness, heat-resisting, wear-resisting, good lateral property and interlaminar shear strength, high temperature and volume stability, and good design ability of material. Therefore, it was first used in aerospace industry.

There are still some issues to be solved for the mass production and the commercialization of metal matrix composite. 1. High temperature is necessary to ensure efficient liquidity of the metallic substrate for it to adequately penetrate into the gap in the strengthened phase to form a composite, wherein adverse interface reaction sometimes takes place between the strengthened phase and the metallic substrate. 2. The compatibility between the strengthened phase and the metallic substrate is poor. 3. The strengthened phase is required to be uniformly distributed in the metallic substrate in accordance with the content and direction specified by the design.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a process for producing aluminum-based composite in order to improve the mechanical strength of an aluminum-based metal.

Another object of the present invention is to provide an aluminum-based composite having better mechanical strength.

Another object of the present invention is to provide an aluminum-based structure having better mechanical strength.

The process for producing aluminum-based composite applies borax on the surface of an aluminum-based metal and heats such metal to a temperature over the melting point of borax.

In one embodiment of the present invention, the aluminum-based metal is aluminum metal.

In one embodiment of the present invention, the aluminum-based metal is aluminum alloy.

In one embodiment of the present invention, borax is mixed with a ceramic material before being applied on the surface of the aluminum-based metal and heated over 743° C., wherein the ratio of the ceramic material with respect to borax is in the range between 0.01 to 90 wt %.

In one embodiment of the present invention, the hardness of the ceramic material is greater than the hardness of aluminum.

In one embodiment of the present invention, the ceramic material is selected from a group consisting of silicon carbide, tungsten carbide, boron carbide, zirconium carbide, titanium carbide, beryllium carbide, zirconium boride, titanium diboride, rhenium diboride, aluminum boride, aluminum oxide, boron nitride, diamond, and the combination thereof.

The aluminum-based composites of the present invention includes 7 to 9 atomic % of aluminum, 11 to 13 atomic % of sodium, and 79 to 81 atomic % of oxygen.

In one embodiment of the present invention, the aluminum-based composites includes 8 atomic % of aluminum, 12 atomic % of sodium, and 80 atomic % of oxygen.

In one embodiment of the present invention, the aluminum-based composites further includes ceramic materials, wherein the content of aluminum is in the range between 2 to 3 wt %, the content of sodium is in the range between 3.5 to 5 wt %, the content of oxygen is in the range between 26 to 27 wt %, and the content of the ceramic material is in the range between 65 to 68 wt. %.

In one embodiment of the present invention, the hardness of the ceramic material is greater than the hardness of aluminum.

In one embodiment of the present invention, the ceramic material is selected from a group consisting of silicon carbide, tungsten carbide, boron carbide, zirconium carbide, titanium carbide, beryllium carbide, zirconium boride, titanium diboride, rhenium diboride, aluminum boride, aluminum oxide, boron nitride, diamond, and the combination thereof.

The aluminum-based structure includes an-aluminum based substrate formed by an aluminum-based metal and an aluminum-based composite disposed in the aluminum-based substrate. The aluminum-based composite includes 7 to 9 atomic % of aluminum, 11 to 13 atomic % of sodium, and 79 to 81 atomic % of oxygen.

In one embodiment of the present invention, the aluminum-based composite includes 8 atomic % of aluminum, 12 atomic % of sodium, and 80 atomic % of oxygen.

In one embodiment of the present invention, the aluminum-based composite further includes a ceramic material, wherein the content of aluminum is in the range between 2 to 3 wt %, the content of sodium is in the range between 3.5 to 5 wt %, the content of oxygen is in the range between 26 to 27 wt %, and the content of the ceramic material is in the range between 65 to 68 wt. %.

In one embodiment of the present invention, the hardness of the ceramic material is larger than the hardness of aluminum.

In one embodiment of the present invention, the ceramic material is selected from a group consisting of silicon carbide, tungsten carbide, boron carbide, zirconium carbide, titanium carbide, beryllium carbide, zirconium boride, titanium diboride, rhenium diboride, aluminum boride, aluminum oxide, titanium oxide, boron nitride, diamond, and the combination thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an optical microscope photo of one embodiment of the present invention;

FIG. 2 is an optical microscope photo of the cross section of a piece of aluminum treated by the present invention;

FIG. 3 is a scanning electron microscope photo of one embodiment of the present invention;

FIG. 4A illustrates the aluminum element analysis result of one embodiment of the present invention;

FIG. 4B illustrates the sodium element analysis result of one embodiment of the present invention;

FIG. 4C illustrates the oxygen element analysis result of one embodiment of the present invention;

FIG. 4D is a scanning electron microscope photo of one embodiment of the present invention;

FIG. 4E illustrates the sodium element analysis result of one embodiment of the present invention;

FIG. 4F illustrates the magnesium element analysis result of one embodiment of the present invention;

FIG. 4G illustrates the aluminum element analysis result of one embodiment of the present invention;

FIG. 4H illustrates the oxygen element analysis result of one embodiment of the present invention;

FIG. 5A is an optical microscope photo of one embodiment of the present invention;

FIGS. 5B-5F are optical microscope photos of different embodiments of the present invention;

FIG. 6 is a photo of an aluminum-based structure having a single aluminum-based composite layer in one embodiment of the present invention;

FIG. 7 illustrates the flexural strength testing result of aluminum metal, an aluminum-based structure of the present invention having a single aluminum-based composite layer, and an aluminum-based structure of the present invention having four aluminum-based composite layers.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention of the process for producing aluminum-based composite applies borax on the surface of an aluminum-based metal and heats such metal to a temperature over the melting point of borax. More particularly, the melting point of borax is 743° C. The aluminum-based metal may be aluminum metal or aluminum alloy.

More particularly, borax is tiled on the aluminum-based metal consisting of aluminum metal, aluminum alloy, or the combination thereof, and such metal and borax are heated over 743° C. in a high temperature environment such as a high temperature furnace to make the aluminum react with borax to form a strengthened phase. During the process, the reaction takes place whether inert gas (e.g. Ar) exists or not. In other words, the aluminum-based metal treating method of the present invention may be conducted in an aerobic environment.

As shown in the optical microscope photo (VHX-5000, Keyence Inc., USA) of FIG. 1, the brighter area represents the aluminum not treated by the aluminum-based metal treating method of the present invention, i.e. the aluminum matrix, wherein the darker area represents the aluminum treated by the aluminum-based metal treating method of the present invention, i.e. the aluminum-based composite. Berkovich hardness and Young's modulus tests are carried out by a nanoindenter (Nanoindenter XP, MTS Inc., USA) at the location indicated by the numbers 1, 2, 3, 4 in the brighter area and at the location indicated by the numbers 5, 6, 7, 8 in the darker area. The results are listed in Table 1.

TABLE 1 No. Berkovich hardness (GPa) Young's modulus (GPa) 1 0.534 71.42 2 0.677 79.19 3 0.655 73.35 4 0.534 76.84 5 4.13 124.4 6 4.33 122.2 7 5.01 132.8 8 4.89 128.5

As shown in Table 1, the mechanical strength of the aluminum treated by the method of the present invention is superior to that of the aluminum not treated by the aluminum based metal treating method of the present invention. More particularly, regarding the aluminum treated by the method of the the present invention, at the locations indicated by the numbers 5, 6, 7, 8, the average Berkovich hardness and Young's modulus are respectively 4.59 Gpa ((4.13+4.33+5.01+4.89)/4=4.59) and 126.98 Gpa ((124.4+122.2+132.8+128.5)/4=126.98). Comparatively, regarding the aluminum not treated by the method of the present invention, at the locations indicated by the numbers 1, 2, 3, 4, the average Berkovich hardness and Young's modulus are respectively 0.6 Gpa ((0.534+0.677+0.655+0.534)/4=0.6) and 75.2 Gpa ((71.42+79.19+73.35+76.84)/4=75.5). In other words, the average Berkovich hardness and Young's modulus of aluminum are raised respectively to 7.65 and 1.68 times the original ones.

The above Berkovich hardness and Young's modulus tests are also carried out on a 5083 aluminum alloy, wherein the results are listed in Table 2.

TABLE 2 No. Berkovich hardness (GPa) Young's modulus (GPa) 1 1.081 72.33 2 1.121 71.88 3 0.983 73.54 4 1.122 70.09 5 4.87 125.8 6 5.22 131.4 7 4.98 121.5 8 5.01 126.1

As shown in Table 2, the mechanical strength of the 5083 aluminum alloy treated by the method of the present invention is superior to that of the 5083 aluminum alloy not treated by the aluminum based metal treating method of the present invention. More particularly, regarding the 5083 aluminum alloy treated by the method of the the present invention, at the locations indicated by the numbers 5, 6, 7, 8, the average Berkovich hardness and Young's modulus are respectively 5.02 Gpa ((4.87+5.22+4.98+5.01)/4=5.02) and 126.2 Gpa ((125.8+131.4+121.5+126.1)/4=126.2). Comparatively, regarding the aluminum not treated by the method of the present invention, at the locations indicated by the numbers 1, 2, 3, 4, the average Berkovich hardness and Young's modulus are respectively 1.08 Gpa ((1.081+1.121+0.983+1.122)/4=1.08) and 71.96 Gpa ((72.33+71.88+73.54+70.09)/4=71.95). In other words, the average Berkovich hardness and Young's modulus of 5083 aluminum alloy are raised respectively to 4.65 and 1.37 times the original ones.

Accordingly, the method of the present invention is able to improve the mechanical strength of an aluminum-based metal.

On the other hand, there exists good compatibility between the aluminum-based metal treated by the aluminum-based metal treating method of the present invention and the aluminum-based metal not treated by the aluminum-based metal treating method of the present invention. FIG. 2 illustrates an optical microscope photo of the cross section of a piece of aluminum treated by the aluminum-based metal treating method of the present invention. As shown in FIG. 2, the aluminum-based metal treated by the method of the present invention bounds well with the aluminum matrix, and there isn't any obvious gap between the two. Accordingly, there exists good compatibility between the two, wherein the binding on the interface is well.

As shown in the scanning electron microscope photo (Nova 230 Variable Pressure SEM (VP-SEM) (at 10 kV accelerating voltage), FEI Inc., USA) of FIG. 3, the darker area represents the aluminum not treated by the aluminum-based metal treating method of the present invention, wherein the brighter area represents the aluminum treated by the method of the present invention. Results shown in FIGS. 4A-4C can be obtained by carrying out element analysis of the brighter area. It can be known respectively from FIG. 4A, FIG. 4B, and FIG. 4C that the brighter area includes about 8 atomic % of aluminum, about 12 atomic % of sodium, and about 80 atomic % of oxygen. Specifically, the aluminum-based metal treated by the method of the present invention is an aluminum-based composite having better mechanical strength. The aluminum-based composite includes 7 to 9 atomic % of aluminum, 11 to 13 atomic % of sodium, and 79 to 81 atomic % of oxygen. Preferably, the aluminum-based composite includes 8 atomic % of aluminum, 12 atomic % of sodium, and 80 atomic % of oxygen.

As a different embodiment shown in the scanning electron microscope photo (Nova 230 Variable Pressure SEM (VP-SEM) (at 10 kV accelerating voltage), FEI Inc., USA) of FIG. 4D, the darker area represents the 5083 aluminum alloy not treated by the method of the present invention, wherein the brighter area represents the aluminum treated by the method of the present invention. Results shown in FIGS. 4E-4H can be obtained by carrying out element analysis of the brighter area. It can be known respectively from FIG. 4E, FIG. 4F, FIG. 4G, and FIG. 4H that the brighter area includes about 12 atomic % of sodium, about 8 atomic % of magnesium, about 7 atomic % of aluminum, and about 73 atomic % of oxygen.

In a different embodiment, borax is mixed with a ceramic material first and then applied on the surface of the aluminum-based metal and heated over 743° C. More particularly, ceramic material having greater strength is added into borax to increase further the mechanical strength such as Berkovich hardness and Young's modulus. The ceramic material is selected from a group consisting of silicon carbide, tungsten carbide, boron carbide, zirconium carbide, titanium carbide, beryllium carbide, zirconium boride, titanium diboride, rhenium diboride, aluminum boride, aluminum oxide, boron nitride, diamond, and the combination thereof. The ratio of the ceramic material with respect to borax is in the range between 0.01 to 90 wt %, and is preferably 66 wt % ceramics material with respect to 33 wt % borax.

In one embodiment, borax is mixed with silicon carbide first, wherein the ratio is 66 wt % silicon carbide with respect to 33 wt % borax. Such mixture is applied on the surface of a piece of aluminum alloys and heated over 743° C. As shown in the optical microscope photo (VHX-5000, Keyence Inc., USA) of FIG. 5A, the brighter area represents silicon carbide, wherein the darker area represents a strengthened phase formed by the reaction between borax and aluminum. It is known that by carrying out tests to the entirety, the Berkovich hardness and Young's modulus tests of the heated metal are respectively 9.7 Gpa and 140 Gpa. Accordingly, with the aluminum-based metal treating method of the present invention, high-strength ceramic material such as silicon carbide can seep into the aluminum phase to strengthen the aluminum-based metal. In different embodiments, silicon carbide in 5083 aluminum composite, tungsten carbide in aluminum composite, titanium carbide in 5083 aluminum composite, titanium oxide in aluminum composite, and titanium oxide in 5083 aluminum composite are respectively shown in FIGS. 5B-5F.

In other words, by premixing borax with a ceramic material and applying such mixture on the surface of the aluminum-based metal and heating the said metal over 743° C., an aluminum-based composite having better mechanical strength containing ceramic material can be obtained. The ceramic material is selected from a group consisting of silicon carbide, tungsten carbide, boron carbide, zirconium carbide, titanium carbide, beryllium carbide, zirconium boride, titanium diboride, rhenium diboride, aluminum boride, aluminum oxide, titanium oxide, boron nitride, diamond, and the combination thereof. The ratio of the ceramic material with respect to borax is in the range between 0.01 to 90 wt %, and is preferably 66 wt % ceramics material with respect to 33 wt % borax .

The above-described aluminum-based composite can be inserted into a aluminum-based substrate to form an aluminum-based structure. More particularly, the aluminum-based structure includes an aluminum-based substrate formed by an aluminum-based metal and an aluminum-based composite disposed in the aluminum-based substrate. In other words, the aluminum-based substrate formed by an aluminum-based metal sandwiches multi-layer reinforcements. As an embodiment shown in FIG. 6, the aluminum-based structure has a single aluminum-based composite layer. In different embodiments, however, the aluminum-based structure is not limited to having a single aluminum-based composite layer, and the aluminum-based composite layer is not limited to being disposed between two aluminum metal layers.

Three-point flexural strength test is carried out respectively to a piece of aluminum metal (no layer), an aluminum-based structure having a single aluminum-based composite layer (1 layer), and an aluminum-based structure having four aluminum-based composite layers (4 layers) to evaluate their flexural strength. The flexural strength test is carried out by a flexural strength testing system (Instron 5900, Instron Inc., USA) under the condition of 3·10⁻⁴ in/s pressing speed and 6 mm distance between adjacent points. As shown by the results in FIG. 7, the flexural strength of the aluminum-based structure having four aluminum-based composite layers is obviously greater than that of the aluminum metal, wherein the flexural strength of the aluminum-based structure having a single aluminum-based composite layer is also greater than that of the aluminum metal. Accordingly, the mechanical strength of the aluminum-based structure of the present invention is better than that of the aluminum metal.

Although the preferred embodiments of the present invention have been described herein, the above description is merely illustrative. Further modification of the invention herein disclosed will occur to those skilled in the respective arts and all such modifications are deemed to be within the scope of the invention as defined by the appended claims. 

What is claimed is:
 1. A process for producing aluminum-based composite, wherein the aluminum-based metal treating method applies borax on the surface of an aluminum-based metal and heats the aluminum-based metal to a temperature over the melting point of borax.
 2. The aluminum-based metal treating method of claim 1, wherein the aluminum-based metal is aluminum metal.
 3. The aluminum-based metal treating method of claim 1, wherein the aluminum-based metal is aluminum alloy.
 4. The aluminum-based metal treating method of claim 1, wherein borax is mixed with a ceramic material before being applied on the surface of the aluminum-based metal and the aluminum-based metal is heated over the melting point of borax, wherein the ratio of the ceramic material with respect to borax is in the range between 0.01 to 90 wt %.
 5. The aluminum-based metal treating method of claim 1, wherein the hardness of the ceramic material is larger than the hardness of aluminum.
 6. The aluminum-based metal treating method of claim 1, wherein the ceramic material is selected from a group consisting of silicon carbide, tungsten carbide, boron carbide, zirconium carbide, titanium carbide, beryllium carbide, zirconium boride, titanium diboride, rhenium diboride, aluminum boride, aluminum oxide, boron nitride, diamond, and the combination thereof.
 7. An aluminum-based composite, comprising: 7 to 9 atomic % of aluminum; 11 to 13 atomic % of sodium; and 79 to 81 atomic % of oxygen.
 8. The aluminum-based composite of claim 7 comprises 8 atomic % of aluminum, 12 atomic % of sodium, and 80 atomic % of oxygen.
 9. The aluminum-based composite of claim 7 further comprises a ceramic material, wherein: the content of aluminum is in the range between 2 to 3 wt %; the content of sodium is in the range between 3.5 to 5 wt %; the content of oxygen is in the range between 26 to 27 wt %; and the content of the ceramic material is in the range between 65 to 68 wt %.
 10. The aluminum-based composite of claim 7, wherein the hardness of the ceramic material is larger than the hardness of aluminum.
 11. The aluminum-based composite of claim 7, wherein the ceramic material is selected from a group consisting of silicon carbide, tungsten carbide, boron carbide, zirconium carbide, titanium carbide, beryllium carbide, zirconium boride, titanium diboride, rhenium diboride, aluminum boride, aluminum oxide, titanium oxide, boron nitride, diamond, and the combination thereof.
 12. An aluminum-based structure, comprising: an aluminum-based substrate formed by an aluminum-based metal; an aluminum-based composite disposed in the aluminum-based substrate, wherein the aluminum-based composite includes: 7 to 9 atomic % of aluminum; 11 to 13 atomic % of sodium; and 79 to 81 atomic % of oxygen.
 13. The aluminum-based structure of claim 12, wherein the aluminum-based composite includes 8 atomic % of aluminum, 12 atomic % of sodium, and 80 atomic % of oxygen.
 14. The aluminum-based structure of claim 12, wherein the aluminum-based composite further includes a ceramic material, wherein: the content of aluminum is in the range between 2 to 3 wt %; the content of sodium is in the range between 3.5 to 5 wt %; the content of oxygen is in the range between 26 to 27 wt %; and the content of the ceramic material is in the range between 65 to 68 wt. %.
 15. The aluminum-based structure of claim 14, wherein the hardness of the ceramic material is larger than the hardness of aluminum.
 16. The aluminum-based structure of claim 14, wherein the ceramic material is selected from a group consisting of silicon carbide, tungsten carbide, boron carbide, zirconium carbide, titanium carbide, beryllium carbide, zirconium boride, titanium diboride, rhenium diboride, aluminum boride, aluminum oxide, boron nitride, diamond, and the combination thereof. 